5.4 - EMF and Internal Resistance Flashcards
1
Q
What is emf defined as?
A
The amount of chemical energy converted to electrical energy per coulomb of charge when passing through a power supply.
2
Q
What is the equation for emf?
A
ε = E/Q
3
Q
What is emf equal to?
A
The potential difference across the cell when no current is flowing.
4
Q
What causes internal resistance?
A
Electrons colliding with atoms inside the battery, therefore some energy is lost before electrons even leave the battery.
5
Q
What is another way of writing the formula for emf?
A
ε = IR + Ir
ε = I(R + r)
r = internal resistance
6
Q
What is the p.d across a resistor known as?
A
Terminal p.d
7
Q
What is the p.d across internal resistance known as?
A
Lost volts because is equal to the energy wasted by the cell per coulomb of charge.
